


Bodies Are Complicated

by TheseusInTheMaze



Series: Eldritch Mark and Doggo Jack [1]
Category: jacksepticeye, markiplier - Fandom
Genre: Anal Sex, Cunnilingus, Extra Body Parts, Fellatio, First Time, Knotting, M/M, Multiple Orgasms, Oral Sex, Overstimulation, Sexual Experimentation, Shapeshifting, Spookgrumps, Squirting, Temperature Play, Tentacles, Vaginal Sex, Weirdness, Weredog, body talk
Language: English
Status: Completed
Published: 2017-08-31
Updated: 2017-08-31
Packaged: 2018-12-22 03:33:28
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 10,186
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11958825
Author URL: https://archiveofourown.org/users/TheseusInTheMaze/pseuds/TheseusInTheMaze
Summary: It turns out, bodies are complicated, regardless of which kind of body you started out with.





	Bodies Are Complicated

**Author's Note:**

> Edited by the truly amazing Angel!
> 
> Written for Rem - love you, boo!
> 
> A heads up - there is a lot of weird stuff in this fic, & I wasn't entirely sure how to tag all of it. If there's anything you'd like me to tag that I missed, please do inform me!

As embarrassing as it was to admit, Jack didn't really notice the big differences in Mark's anatomy until summer had rolled around.

Which wasn’t to say that Jack hadn't noticed that Mark's body was... well, different - they'd had sex before, there had been cuddling and sleeping next to each other.

Mark by now knew that Jack tended to piss with the door open in the mornings, and Jack knew that Mark snored and sometimes grew extra limbs when he was talking in his sleep.

But there was... other stuff, that Jack honestly hadn't thought of, until they'd been living together for about two months.

For one, there was the body temperature thing.

Jack liked to be warm - he would sleep wrapped up in his own separate blankets so he could properly burrito himself, and he'd drink hot tea, even when it was pretty warm out, because he hated when the cold got into his bones.

But when summer comes around, even the most endothermic of us needs to cool down now and then.

At which point he realized just how cool to the touch Mark was.

* * *

Jack flopped into bed, panting, his eyes shut. He was flat on his tummy, his limbs pressed close to him, his face in the pillow.

"Why'd we move to fuckin' California?"

"To make it big in show business," Mark said.

He was lying on his back, reading from his phone.

"You make it sound like we're plannin' to debut on Broadway or something," said Jack.

"Wrong coast for that," said Mark.

Jack snorted.

"But it's so damn _hot_ , and our air conditioning is butts."

"I thought you liked butts," said Mark.

"I like your butt," Jack said, "and genuinely well maintained butts. But this is a boggy, manky butt that's not seen a shower or a piece of toilet paper in an age."

"... ew," said Mark. "That's disgusting."

"So is this weather," said Jack.

He rolled on top of Mark, the very picture of melodramatic, and then he yelped and shrank back.

"You're cold," Jack said.

"Well, yeah," said Mark. "I'm kind of made of the same stuff as the void."

"I guess I knew that logically," said Jack, "But I honestly... hadn't thought of it otherwise."

"I can go take a warm bath, if that'd help a bit? Or get under an electric blanket?"

"No, no," Jack said quickly.

And then he was on top of Mark, his arms folded, his chin resting on them so that he wasn't digging into Mark's sternum.

Mark grunted in surprise, but he didn't seem to mind.

He dropped his phone off to the side of the bed, and he grabbed Jack's ass, squeezing it, as Jack's tail began to wag.

"You feel like a furnace," Mark complained.

"D'you want me to get up?"

"I didn't say that," Mark said quickly.

He gave Jack's butt another squeeze.

"It's like sitting next to my own fridge," Jack sighed, and his tail was wagging harder, as he nuzzled under Mark's chin, kissing along it gently.

Mark tasted like cold, and a bit like the stale chocolate of the void, but he mainly tasted like himself, which was all that Jack could ask for.

"Would you ever be interested in, um... in some more unorthodox sex?"

Mark looked embarrassed.

"What do you mean?"

Jack's tail was slowly wagging, back and forth, almost lazily.

He was cooling down, from the belly up towards his back.

It was like heaven.

Enough like heaven that he was beginning to get a boner, which was... a bit awkward, but fuck it.

"Usually when we have sex, I... you know, give myself the more standard set of genitals. And they're about the same shape as a human's, but they're not exactly... my original set. And I'm kinda curious if you'd ever be interested in playing with, you know, the original parts."

"You sound like you're talking about a computer," Jack said, licking gently along the stubble of Mark's jaw.

"Is there a non awkward way to talk about the fact that I'd like you to try interacting with my naughty bits?"

"Not really," said Jack, and he laughed. "There isn't a lot of information on this shit, is there?"

"Not really," said Mark. "There aren't a lot of folks like me getting into, like, consensual relationships with mortals."

"No?"

"No," said Mark. "Although at that point things get complicated to a point that even I get confused."

Jack snorted.

"So what do you have, anyway? Some kind of weird mutant penis?"

"... tentacles," Mark said. "Sort of."

"... sort of tentacles? How does that work?"

"Well, they're like..." Mark made vague hand motions. "It's complicated."

"I can live with complicated," Jack said, and then he made a happy noise, as Mark began to scratch his scalp, right between his ears.

"You wanna do anything... you know, sexy?" Mark waggled his eyebrows.

Jack snorted.

"It's too hot," he told Mark. "Like, lying on top of you like this is awesome, and I'm beginning to think that maybe I won't have to turn the shower on to super cold, but it's still so goddamn hot that I just don't want to move."

"I could give you a blow job," Mark suggested. He was blushing. "I like the idea of... you know, helping you cool down, while also getting you off."

"Can I give ya a rain check on that one?" Jack nuzzled along Mark's jaw. "This is so nice."

"Fair enough," Mark said, and he wrapped his arms around Jack, squeezing him tightly.

* * *

"Can I ask a weird question?"

It was two days later.

The air conditioning still hadn't been fixed.

"What's up?"

Jack was drinking a glass of ice water, occasionally pressing the cold glass against the back of his neck.

"What does being hot... like, feel like?"

"What do you mean?"

"I've felt warm," Mark said. "Obviously, even as cold as I am, I can get warm sometimes, although it's kind of... strange."

"Being too hot is like... okay, you ever put, like, an ice cube in a hot pan of water?"

"No."

"Okay. But it's like... heat coming out of you, and also heat coming into you, from the outside, until you feel trapped in this personal bubble of misery, and everything is too tight and uncomfortable, but you can't really do anything about it."

"... huh," said Mark. "That sounds like it feels interesting."

"I guess it is, if you've never experienced it?" Jack shrugged. "But I don't like it."

"Would it be easier if you shape shifted?" 

"God no," Jack said, and he shook his head rapidly. "Then I'd have all that fur to contend with!"

"Is there any way I can help you... cool down?" 

Mark was sidling closer, and one of his hands was on Jack's hip now, hooked into his belt loop, pulling Jack closer. 

"I'm sure you can think of a way," said Jack, and he was grinning. 

Jack put the glass down on the counter, and he draped his arms over Mark's shoulders, pressing his forehead against Mark's, then leaning in to kiss Mark, his tail wagging. 

* * * 

Mark tasted like cold.

Not like a particularly cold anything, just like cold in general. 

It was hard to describe - almost like that feeling, when you go out into the air on a winter day and it feels a bit like the air has just punched you in the chest.

Only not, because in this case it was just situated in one place - against Mark's mouth.

Mark grabbed Jack's ass, squeezing it, as Jack's tail kept wagging, and they pressed closer together, as Jack's cock started to get harder.

"Are you... are you not enjoying this?" 

Jack pulled back, panting, his long tongue lolling out.

"Oh, I am," Mark said, his voice going down to its sexiest almost growl. "I'm just, um... I'm just kind of... remember how you said you'd be willing to try my original parts a bit?"

"Yeah?"

"Well, I've got my original... set right now, and it reacts kind of different." 

"What kinda different? Is it gonna spew acid on me or something?"

"Oh, nothing like that," said Mark. "Just, uh... it feels different."

"As long as I'm not gonna have my fingers eaten, I think I'm good," said Jack. 

"... why would I eat your fingers?"

"Not you eating my fingers," Jack said. "Your dick. Or whatever it is that you've got instead of a dick."

"How would my dick eat your fingers?"

"I don't know," Jack said defensively. He ground his erection against Mark's thigh. "I'm a little distracted right now, if ya must know!"

"Okay, okay," said Mark. "I could help you with that...."

"Lend a little hand, maybe?" 

Mark snorted, one hand between Jack's legs, squeezing his cock, palm curved around the head. 

"Are you calling my hands small?"

"Oh, f-f-far from it," Jack panted. "Far, far from it."

He chuckled in the back of his throat, roughly, and he humped against Mark's hand harder, as his cock throbbed.

Mark was cold, the kind of cold that is almost an entity in and of itself, and it was a blessing, against Jack's overheated skin. 

Jack pressed closer, and he was licking along Mark's jaw, Mark's stubble rough against his tongue, as he rolled his hips against Mark's thigh, full on humping Mark's leg like a beast. 

Every bit of Jack that was touching Mark was cold.

It was perfect.

"Hey Jack?"

"Mmm?" 

Mark was trembling. 

"I... I really want to touch you. With my original bits."

Jack pulled back, still leaning back against the counter, and he looked Mark in the face, trying to read his expression. 

"What kind of original bits do you have?"

".. tendrils? Tentacles?" Mark shrugged, looking self conscious. "I'm not entirely sure how to describe them." 

"Can I see them?"

"I don't wanna freak you out," said Mark. 

"If I'm freaked out, I'll tell you," Jack promised. "I've watched tentacle hentai. How different can it be?"

"... I'm not sure if I'm insulted or reassured," said Mark. 

"Go with reassured," Jack suggested. "What would you like me to do?"

"Let me just... take my pants off," said Mark, and he was shoving his pajama pants down around his thighs, and there was... Mark's genital slit.

Jack had seen that before - sometimes Mark didn't manifest himself a dick when he was showering, or looking for his clothes.

But now it seemed to almost be... pulsing. 

Jack reached out, cautiously, and he squeezed between Mark's legs, where the slit was, the very tip of his finger against the line of the slit. 

"Oh," Mark murmured, and his hips rolled forward. "That's... that's nice."

"Does stuff... is it gonna come out of there?"

"Yeah," Mark said thickly. "Do you wanna see?"

"Yeah," said Jack. "I'd like to, if that's okay."

"I wouldn't have offered if I wasn't okay with it," said Mark, and he laughed. "This feels so awkward."

"Why?"

"Because we're different species," said Mark. "And most folks get, you know, weirded out by this kind of thing."

"Would you feel better if I changed?"

"That might help," said Mark, and he laughed. "You're the first mortal I've ever really done before."

"Ooh, you're doing me?"

"I mean, I thought we were under the impression that you were being done on the regular," said Mark. "And, uh, I meant doing this with."

Jack was aware of just how surreal this was - here he was, about to change back into his dog form, about to stand in his kitchen at three in the afternoon and look at his boyfriend's dick, when it wasn't actually a dick, but possible a collection of dicks or... something? 

What the actual fuck?

But he watched, as Mark's genital slit spread open, and then there was... something coming out, a collection of somethings, and they wriggled and flailed in the warmer air of the kitchen.

It was like someone had dropped ink in a cup of water, and each of those tendrils of ink had become 3D, and now they were waving in the air.

"Can I... can I touch it?"

"Sure," said Mark, and he cleared his throat. "It's probably gonna feel kinda... weird, though."

"I can deal with weird," said Jack, and he reached a hand down, his fingers outstretched.

Mark's tentacles laced through Jack's fingers, wriggling and grasping them, and Jack squeezed, gently.

Mark moaned, his hips rocking forward.

"What's it feel like?" Jack looked down at his hand, then up at Mark's face.

"It's... it's kinda... like... it's nice pressure," Mark said, and he was blushing. "Sorry. I can't entirely understand how to describe it. But I like... they want to be someplace tight and wet." 

"Sounds like most dicks," Jack said, his tone teasing. "Do you want me to put my mouth on you?" 

"What, there?" 

"Yeah," said Jack. “Assuming there means on your dick.”

"Well, my... tentacles," said Mark, and he looked embarrassed. "If you'd like." 

"I wouldn't offer it if I didn't want to," Jack said, in a long suffering voice. 

They could go back and forth on this shit for hours.

So Jack got on his knees, and he took a handful of tentacles, and aimed that at his mouth, holding them like a collection of especially wiggly pipe cleaners.

The tentacles patted along his face, the very tips of them slippery with some kind of goo, and when he let go, they kept exploring his face, a few of them reaching out for his ears, one going towards the inside of his nose, which made him sneeze.

And then they were going in his mouth.

He closed his mouth, careful of his teeth, and they wriggled, as he sucked, the sensation alien and terrifying, but hot, in a weird way.

He rubbed his cock through his pants, and he began to suck a little harder, as Mark made... some kind of noise on top of him.

"Fuck, you're so _warm_ ," Mark gasped, and he was thrusting forward, his hands in Jack's hair, tangling it around and around his fingers. "You're so... oh!"

He rubbed Jack's ear between his fingers, seeming to enjoy the silkiness of it, and Jack hummed.

The tentacles in Jack's mouth began to stiffen, which was... strange, but they were still feeling along his teeth, the insides of his cheeks, and that was... he wasn't sure how he felt about that, but he stayed still.

It was easier to keep from gagging than with a regular cock, at least. 

He sucking, and was aware of the drool going down his chin, leaving him a puddled, sticky mess. 

"You're just so _warm_ ," Mark sobbed, and then he was shuddering, clinging to Jack, as the tentacles in Jack's mouth convulsed, and something thick and viscous slid down Jack's throat, leaving Jack gasping, groaning. 

Jack spat out the cum that was gathering in his mouth, let it drool out of the corners of his lips, and he made a face - his tongue was now so cold that he couldn't feel it. 

But Mark was slumping down onto the floor next to him, panting harder, and Mark's tentacles were retreating, back into Mark's body. 

"Fuck," Jack said thickly, and he leaned into Mark, as his own overheated body began to finally, finally cool down. 

"Did I do okay?" Mark sounded genuinely worried. 

"You did great," said Jack, and he laughed. "Shouldn't _I_ be the one worrying about how I did?"

"I mean," said Mark, "I've never really had a mortal interact with my tentacles like that before, so I was worried maybe they acted weird or something like that, you know?"

Jack was still chuckling.

"You are such a weirdo," he told Mark, as he sprawled out flat on the floor, the tile cool even through his t-shirt.

"Let me make it up to you," Mark said, and he began to kiss along Jack's ankle, through Jack's jeans. 

"Mmm?"

Jack raised an eyebrow.

"Oh, totally," said Mark. "Since you did such a good job, I should totally return the favor."

Jack snorted.

"You don't have to, you know," he said.

"I know I don't have to," Mark said, in a belabored voice. "I _want_ to."

And then he was grabbing Jack's pants and just... yanking them down.

Didn't even unbutton them, which, okay, ow, but Jack's cock was springing free, pressing against Jack's belly.

"Can I suck it?"

"I'd love for you to ride me, if that'd be okay," said Jack. "I like seeing your face, when you're doing shit like this." 

"You can see my face when I suck you off," Mark pointed out. 

"Well, yes," said Jack, "but not up close and personal, and that's what I'm in the mood for."

"Fair enough," said Mark. "Do you want me to use a different hole?"

"... what?" 

Jack got up on his elbows, as images he didn't want to look too closely began to dance through his head.

Mark was blushing.

"Well, you know how I can, like, have a penis if I want to?"

"You can technically have _two_ penises," Jack said, cheeky, "since you can always play with mine."

Mark snorted, and prodded Jack in the side.

Jack prodded him back.

"Well, uh, I haven't done much... experimenting, but I have to admit, I'm kinda curious about, like... trying a new set up. Of reproductive organs."

"A new set up."

"Yeah," said Mark. "I could give myself a vagina or shit like that, if you'd like."

"What, really?" 

Jack tried to picture Mark with a vagina... and paused. 

That might be interesting. 

But also weird. 

"Can I just like... fuck your face for now, please?" 

Jack laughed, self conscious. 

Wow, but did he sound like a creep. 

"Actually, I really wanna kiss you right now. I wanna... I wanna do a lot of things. But if you wanna suck me off, I really... I very much would not be opposed."

"... could you have made that sound any less weird if you tried?" Mark nuzzled at Jack's belly, kissing along it. 

"I'm sorry, I've literally just had the semen of the void -"

"The semen of the void?!"

"You know what I mean," Jack said. "My mouth still feels weird." 

"Would you rather not give me blow job type things?"

"No, no," Jack said quickly. "I like doing it, like, a lot. I'm just a little...." He made vague hand motions.

Mark laughed, and he kissed Jack on the stomach again, beginning to rub Jack's sides with his fingertips.

Jack squirmed, his shirt beginning to ride up, his toes curling against Mark's sides.

"You're so warm," Mark said. "I can even feel your heartbeat, a little bit."

"You can't feel yours?"

"Not really," said Mark. "The thing that keeps me alive is... much more complicated than that. I can grow a heart, if I need to, but for the most part, it's all a mix of things."

"Does it bother you, that my body is so weird?" 

"I don't think it's that weird," said Mark. "It's just so... different, you know?"

"Do you want me to change shape?"

"If you wanna," said Mark. "I like you either way."

"It's too damn hot for all that fur," said Jack, and he stayed flopped over.

"Fair enough," said Mark, and he was kissing lower, nuzzling into Jack's cock.

His mouth was... cold, which was a bit of a strange sensation - coldness wrapped around his dick, cold hands holding on to his thighs, squeezing the meat of them, and Mark's mouth beginning to slurp, bobbing up and down, leaving Jack shivering, cold and overheated at the same time.

He rolled his hips up, his cock beginning to swell.

He didn't have a sheath when he was in this shape, which was... vulnerable as hell, but also it let him breathe, and at least he wasn't circumcised. 

The idea of that much dick just being... available and on display.....

But why worry about it, when Mark was sucking and licking along his shaft, when Mark was nosing at his balls, sucking them into his mouth, and Jack's back was arching, his toes curling, his head thrown back. 

His knot was going to pop soon, as Mark's mouth found the head of his cock again, and Mark's mouth was swirling around the head, and then Mark was fucking... deep throating him, taking Jack's dick so far down that there was cold against Jack's belly, but there was heat in the pit of Jack's stomach, as the pressure finally snapped, and he was cumming and cumming, into Mark's mouth, and the eldritch abomination swallowed it all down, making pleased noises around Jack's cock. 

Jack shuddered, arching off the bed, and then he was flopped out flat on the floor, staring at the ceiling. 

"I can't believe we just fucked in the kitchen," said Jack, as if to thin air. 

"Have you never actually fucked in a kitchen before? Is that not a thing that people do?"

"I mean," said Jack, "it probably is."

He was absently running his fingers through Mark's hair. 

"It is in the pornos."

"But they're pornos," said Jack. "When was the last time you saw someone come in with, like, their dick in the middle of a pizza or something."

"I could spank you with one of the spatulas, if you'd like," said Mark, indicating vaguely up at the counter. 

"Or you could not," said Jack, and he yawned. "I do use those to make food, ya know."

"Your butt is clean," said Mark.

"It's the principle of the thing," said Jack.

Mark snorted.

"But you're fine fucking on the floor?"

"Well, that's different," said Jack, and he prodded Mark with his foot. 

Mark grabbed his foot, and he kissed the sole.

Jack squealed, and tried to pull his foot back. 

* * * 

It got cooler - thank any gods that did or didn't exist that it actually got cooler.

And Jack was in his dog form, fully dressed, and he was wagging his tail. 

He might have had his face in a carton of ice cream, but Mark didn’t have to know that. 

Except there was a hand on Jack’s shoulder, and Jack’s tail stood straight up - he barked, and he dropped the ice cream.

“Mark! I thought you were grocery shopping!”

“I was,” said Mark, and he snorted. “I did have to come back. I brought you food.”

“Food?” 

Jack’s tail began to wag, and he pressed closer to Mark, nuzzling under Mark’s chin with his sticky, furry muzzle. 

Mark snorted, as Jack began to dig through the bags, sticking his whole face into the bags, his tail beginning to wag harder.

“You’re such a weirdo,” said Mark. 

“Just because you have to remember how to make yourself enjoy things doesn’t actually mean that those of us who _do_ enjoy things aren’t weird.”

Mark snorted.

“Didja bring anything interesting?” Jack was still nosing through the groceries.

Mark flicked Jack on the nose.

Jack nipped Mark’s hand. 

“You’re such a brat,” Mark said.

Jack growled, playfully, and he shook his head back and forth, his ears perking up and his tail wagging. 

He wasn’t biting hard enough to do much more than give a bit of pressure, and hie was getting drool all over his fingers. 

“Are you gonna be a good boy?” 

Jack’s ears went back, then perked up. 

“Woof,” he said, deliberately.

Mark pulled Jack closer, and Jack’s tail wagged faster. 

Jack began to lick Mark’s face, and Mark was making a disgusted noise. 

“Your tongue is so damn cold!”

“How can you even tell if my tongue is cold, when you’re a goddamn ice cube yourself,” Jack grumbled, nuzzling and pressing closer, still wagging his tail. 

“I just can,” said Mark.

He reached out to grab Jack’s ass. 

“I want to do a thing,” Mark said in Jack’s ear. “How would you feel about that?”

“I’d ask what kind of of thing you wanna do, but judging by your hand placement, I’ve got an idea along those lines..” 

“Hmmm?” 

Jack ground his hips against Mark’s, and he was wagging his tail faster, beginning to lick Mark’s face.

“You wanna fuck me, don’t you?”

“... actually,” said Mark, and he sounded embarrassed, “I’m kinda… curious how you work in these… that is, when you’re wearing this shape. I’m curious how everything works.”

“What do you mean by everything?”

“... why do you have so many nipples? Like, how many do you have?” Mark laughed, squirming a bit. “I mean, why do you have them in the first place?”

Jack blinked.

He wasn’t sure what he had been expecting, but this hadn’t been it.

“Well,” said Jack. “Um. It’s, uh… all people start out when they’re in the womb as female, but some of us don’t come out that way. It’s… like, super complicated, honestly.” 

"... huh," said Mark. "So, how about, instead of fucking around on the floor of the kitchen, we actually fuck on the bed, so that my knees aren't killing me?"

"You're an eldritch abomination that lives in the void. How can your knees hurt you?"

Jack stuck his long tongue out, waggling it at Mark cheekily.

Mark rolled his eyes, prodding Jack gently in the side. 

Jack prodded him back.

"How about you, uh... how about you go to the bedroom and take care of a few things, and I'll put away the groceries."

Jack snorted - Mark was always a bit squeamish about the needs of anal sex, which struck Jack as fucking hilarious, considering the fact that he was literally made of the same stuff as the void that devoured at the very edges of creation, but then again, we all have the things that gross us out. 

So Jack went to the bathroom and set out the various necessities needed while fucking around.

His ears twitched every time he heard a noise from the kitchen - Mark talking quietly to himself, putting things away, whistling occasionally. 

Jack... well, took care of some stuff, and then he was coming out of the bathroom, and there was Mark, sprawled out on the bed, stretched out like some kind of indulgent cat.

Jack's tail was wagging. 

"I want to do things to you," Mark said. "But I want to just do them to you, not just us doing things for each other."

"You want me to Bottom, huh?" Jack waggled his eyebrows.

Mark snorted, and his inky tendrils were emerging from his back, and they were grabbing at Jack's wrists, pulling them closer.

Jack shuddered - it was cold, and it was... it was the kind of intense that he loved, but they didn't do that much. 

It took much effort - it's easier to mess around with someone, grinding and making out. 

But now Jack was flat on his back on the bed, his pajama pants low around his hips, and Mark's long cold fingers were sliding along the thin fur of Jack's belly.

"You're cold," Jack mumbled, as Mark found Jack's top set of nipples. 

"I can go take a hot shower," said Mark. "If you'd like, I mean."

"Nah," said Jack. "There are people who like shit like ice cubes. We can be extra kinky."

"We can do tons of kinky stuff," Mark said agreeably. "What happens if I do this?"

He tweaked Jack's nipples, both hands on Jack's chest, and Jack made a surprised noise, his hips rocking upwards. 

Mark's other tentacles were pulling on Jack's pants, shoving them down, and there were cool tendrils tickling along Jack's dick, his thighs, cradling his balls.

"You're so hot," Mark said. "And furry."

"I'm hot and furry, yeah," said Jack. "It's part of being a dog." 

Jack laughed, slightly shrill, while Mark licked Jack's nipples, while Jack's cock was cradled and stroked by those cold, cold tentacles.

"I can feel your heartbeat," said Mark. 

"You keep s-s-saying... that," Jack said, but he was losing his train of thought, as Mark's tentacles were sliding along his sheath. 

His cock was beginning to emerge from the fur of it, and the hot, red flesh was throbbing as the tip slid into view.

"I don't have one," said Mark. "Sometimes when I can't sleep, I like the feeling of... it makes me feel like I'm a person, sort of. I mean, I'm a person in that I exist...." Mark paused. "This isn't sexy."

"Not really," Jack admitted, tugging gently at the tentacles restraining his wrists. "It's insightful, though, if you wanna have an insightful conversation?"

"I don't want to have an insightful conversation," said Mark, and the tentacles around Jack's cock squeezed, hard enough that Jack groaned like he'd been shot in the gut. "I want to make you cum so hard that you forget your own name."

His voice went down to a sexy growl, and Jack shuddered, the cold beginning to seep into his bones, which was making his toes curl and his cock throb.

He was going to end up with a fetish for being cold. He'd go walk in the snow some day, and have an erection.

He snickered a bit too himself, but it turned into a moan, as a tendril slid into his mouth.

It tasted like cold.

Mark's tentacles began to stroke along Jack's cock, and the very tip of Mark's tentacle slid into his sheath. 

Jack groaned, covering his face with both hands, as the cold tendril slid along the heat of his cock, trapped in the sheath.

"How does that... how does that feel?"

Nobody had ever put anything in Jack's sheath before - he was curious, admittedly.

"It's... it's tight," Mark breathed, and he was shuddering. "It's really tight, and it's hot. Slippery."

"Slippery?"

"You're dripping a lot," said Mark. "Can I... can I put it in your dick?"

"... not in my dick," said Jack. 

"I'm curious what the... can I just probe a little bit?"

"You make me nervous using the word probe," said Jack, and he laughed, anxiety bubbling out of his throat. 

"Fair enough," said Mark, and his tentacles kept rubbing along Jack's sheath, as Jack's cock began to pop out more. 

Jack was wriggling, panting, his tongue lolling out - he was well on his way to overstimulation, between the nipple attention, and what was happening to his cock, to say nothing of the way that some of Mark's other tentacles had begun to fan out, stroking along his sides, going to his hips, cradling his balls, even beginning to circle Jack's asshole. 

"I want to penetrate you," Mark said thickly. "Can I? I've wanted... your mouth feels so good, your ass has to... it has to...."

"Please," Jack said, and there was a touch of begging in his voice now. " _Please!_ " 

Mark's tentacle slid into his ass, lubricated by whatever that weird substance that he managed to excrete, and it was cold enough that Jack was probably gonna start shivering, but it was sending goosebumps all through Jack's body, and then the tentacle was pressing firmly against Jack's prostate, and Jack's cock jerked, more pre dribbling along the shaft, all over Mark's tentacles. 

The very tip of one tentacle slid into the very tip of his cock, then pulled back, and Jack sobbed. 

It was... intense. 

It was more cold, filling inside of him, and his cock was throbbing and twitching, as the tentacles undulated around his cock, the other tentacles caressing his balls, almost kneading them. 

Jack was still humping up, his eyes closed tightly, and he was cold - ribbons of cold filling him up like he was ice cream, although that led his brain onto some other tangent, the train nearly derailing, and he was almost laughing as he let the pleasure overtake him.

Jack’s cock swelled, his knot popping out of his sheath, his whole cock now surrounded by the tentacles, which were squeezing his balls, then pressing under him, swelling inside of his ass. 

“I'm going to cum,” Mark said thickly. “Can I cum in you?”

“Sure,” Jack panted, his tongue lolling out. “G-go for it.”

“... go for it,” Mark said, deadpan, and he twisted the tentacles all at once, so that they practically spun inside of Jack, leaving Jack's toes curling and his eyes rolling back in his head. 

“Shut up,” Jack growled, and the growl crested into a howl as he came, his knot throbbing as it was squeezed, his ass clenching around the squishy firmness of the tentacles inside of him. 

The tentacles around his cock milked him, squeezing his balls, and there was more cum gushing out of him, to drool down the shaft of his cock as he shuddered. 

“Fuck,” Mark groaned, and the tentacles moved faster, faster, until Jack was being covered by some cold translucent stuff, inside and out. 

It was tingly, and bits of Jack were starting to go a little numb. 

“Holy shit,” Jack mumbled, and he wrapped his arms around Mark, cuddling Mark, pressing the top of Mark’s head. 

“Go for it?!?!”

“... shut up.”

* * * 

“Can I ask a weird question?”

Jack was taking a bath, noodling around on his phone, as Mark came into the bathroom to wash his hands.

“What’s up?”

Mark leaned against the sink, his arms crossed. 

The shadows of his tentacles could be seen in the mirror.

“Do you go to the bathroom?”

“Well, yeah,” said Mark. “I’m in here, aren’t I?”

“Not what I meant,” said Jack.

“Yeah, I know,” said Mark, and he smiled, his teeth very white. “And I mean… I could? If I tried?”

“Well, why do you cum?” Jack sat up, his elbows on his thighs, leaning in, his toes above the water. 

“Because it just… feels right to do so,” said Mark. “Like… I could formulate actual semen, like you have, if I really tried to.”

“Could you get someone pregnant?” 

“... I’d never thought of that.” Mark expression turned thoughtful. 

“So you’re not sure?”

“I mean,” said Mark, “I feel like that’s one of those things you don’t really have an accurate way of testing. Because, like… you know, any offspring I had would be some kind of star spawn that might eat the very Earth itself -”

“Someone’s got a high opinion of himself,” said Jack, leaning back into his bath water.

Mark stuck his tongue out at Jack.

Jack stuck his tongue out back.

“I’ve, um… I’ve experimented with, you know, my own body - I’ve tried all the usual ways of… voiding.”

“You make it sound so gross when you describe it like that,” Jack complained.

“Because saying “I taught myself how to take a shit when I had a corporeal body for the first time” is so much better?!”

“... well, okay, no,” said Jack. “But… still!” 

“Still?”

“I’ve seen you eat. What happens to it?”

“It gets absorbed into the void,” said Mark, as if that was a totally normal thing to say. 

“Well, yeah,” said Jack, and he sank down lower into his bath. “Obviously. The most obvious thing in the world.”

“You’re too sarcastic,” Mark said, sitting on the edge of the tub and ruffling Jack’s wet hair. 

Jack was still human shaped, so the whole room didn’t smell like wet dog.

Mark scratched around the base of Jack’s ears, and Jack’s left foot began to kick, just enough that the water began to splash.

Mark moved lower, growing another pair of arms out of his torso, and those were rubbing Jack’s chest - another set going for Jack’s chest, scratching along it gently, pausing to flick at Jack’s nipples, which was enough to make him squirm even more, as his tongue lolled out, his eyes sliding closed.

He was wearing his blissed out canine look - he could always tell when that was happening. And he was getting hard, but that wasn’t important, because there was another pair of hands on his tummy, scratching it, rubbing it, enough to make him wriggle and pant, almost squeaking.

“You’re so cute,” Mark said. “I can’t fuckin’ get over how cute you are.”

“I’m not that cute,” Jack protested.

Mark booped him on the nose.

Jack sighed, his eyes crossing, and then there were yet _more_ hands on Jack’s dick, jerking him off leisurely, almost luxuriously, as Jack squirmed in the bathtub, the water slopping onto the floor.

“I can feel your muscles moving,” said Mark. “When you twitch, I can feel the shadow of your nerves, and they’re bunching under your skin, every time you move there’s just this… it’s like an earthquake, only it’s localized, and it’s so small that it wouldn’t matter, except it _does_ , because it’s your body.”

“... what?” Jack looked at Mark, confused, addled by arousal and the overstimulation that was filling his nerves like the water that was sloshing out of the tub. 

“It’s just so… amazing,” Mark breathed, and the look he was giving Jack was honestly a bit unsettling, as his hands stroked and pressed and tickled and pumped, all over Jack’s body. “You’re nothing but meat and electricity held together with… something or other, we don't even know what it is that makes you hold together, but it’s all things that are… there, and it leaves you alive and yourself….” 

"You sound awfully... awfully hippy dippy," Jack mumbled, and he was humping up into Mark's hands, grabbing tightly to the sides of the tub as he planted his feet on the bottom of it and thrust upwards.

"What does that mean?" 

"It doesn't fucking m-matter what it means, because... I'm... oh, _fuck_!"

Jack came. 

The pressure snapped like a broken bone, and the hands on his dick were milking it, squeezing it, getting every last drop of cum out of him, as his hair was pulled and who even knew how many pairs of fingers dug into the soft flesh of his stomach, his thighs, his chest.

He flopped back into the water, panting, his tongue lolling out and his tail slowly wagging.

"Hi," he mumbled to Mark, licking one of the hands.

"Hi," said Mark, and he reabsorbed all the hands but his original two. 

Jack checked over the side of the tub, where he'd chucked his phone when things had started to get hot and heavy. 

It was still dry and in one piece.

Thank everything for those shock absorbing phone cases!

"That was fuckin' amazing," he told Mark, and he was grinning, his tongue lolling out.

"Thanks," said Mark. "So are you."

Jack snorted, but he was blushing.

"Do you want, uh... do you want any help of some kind?"

"Nah," said Mark. "I really just wanted to touch you." 

"... oh," said Jack, and he blushed harder, his ears flattening.

Mark put his hand under Jack's chin, making Jack look up into his strange, spooky eyes.

He kissed Jack, and Jack kissed him back, tasting the void and the darkness between the stars.

* * * 

"I'm going to try a thing today," said Mark, about two weeks later.

"What kind of thing?" 

Jack was washing dishes after dinner, his tail swishing back and forth lazily.

He liked to do the dishes - there was something meditative about it. 

"Well," said Mark, "uh, more accurately, I've, uh... I've _been_ trying a thing today."

"Yeah? What've you been trying?"

"To have a working penis."

"... wait, what?"

Jack turned around, his hands dripping dish water down onto the floor. 

"I was curious, after you were talking about whether I could make sperm or not, and I wanted to see if I could make the whole... mess of it," said Mark. "Like, all the fiddly parts on the inside, see if I could make sperm, everything."

"What did you have before?"

"Kind of... like a dildo, only I could feel it?"

"... huh," said Jack.

"But I want to see if it works, like, naturally," said Mark. "If you'd like to. Later, I mean."

"I'd be curious," Jack admitted. "Could be fun."

Mark smiled, and he looked bashful. 

"I hope it's good enough for you!" 

"Anything you do is good enough for me."

"What, really?"

"Well, okay, not anything-anything, but... like... if you're trying to try what it's like to try new stuff, I'm gonna fully support that."

"Yeah?" Mark grinned, crooked. "I'm glad to have your support as I attempt to replicate your strange reproductive system."

"How does your reproductive system work, then?" Jack stuck his tongue out. 

"Well," said Mark, "for one, it begins with a dying star."

"... fair enough," said Jack, and he laughed. "Well, uh, I'll leave you to your semen production for now, okay?" 

"It takes a surprising amount of effort," Mark said. "How do you do it?"

"Most of it is pretty automated," said Jack. "If my ancestors had needed to sit around and think about how their bodies worked, I don't think they'd have ever gotten around to actually making babies or eating or other vital stuff."

"It took me almost a century to figure out how sleep worked," Mark said, and that was always a bit of a shock - the fact that Mark was a good deal older than civilization. 

"What'd you do in the interim?" 

Jack went back to washing dishes, up to his elbows in the hot, soapy water.

"Mainly I lay in a coffin and tried to figure out how to fall asleep," said Mark.

"Wait, a _coffin_?!"

"I figured a coffin wouldn't be bothered," Mark said, looking sheepish. "Of course, someone saw me get out, and then there was... kind of a mess...."

"Please don't tell me you were the one who started the whole vampire mythos," said Jack, in a longsuffering voice.

"... probably not," said Mark, although he sounded a bit uneasy. But then he cheered up. "But when I figured it out, I slept for twenty years."

"Which twenty years?" 

"I think one of the World Wars," said Mark, his expression thoughtful. 

"... huh," said Jack. 

"I'm gonna go work on my show," said Mark, and he kissed Jack on the back of the head.

Jack leaned into the kiss, and he smiled.

"Good luck on your semen production," he called out, as Mark made his way to his studio.

He could practically hear Mark rolling his eyes.

* * *

Mark emerged from his editing cave at dinner time, looking slightly worse for wear. 

"Making semen takes _energy_ ," he said, which made Jack burst out laughing. 

"What?"

"I've been doing it, all evening," said Mark. "I gave myself the whole shebang, even the fiddle bits like the vas deferens, and it's all... I don't have to concentrate on it too hard, but it's surprisingly tiring!" He flopped onto a chair, and he leaned back into it, stretching, his shirt riding up to reveal his belly. 

Jack stared at it, licking his lips. 

"Do you need to concentrate especially hard?"

"I kind of... set things working on their own there," said Mark. "But I don't know if I could make more than a load of this - it's pretty tiring."

"Do you think it'd be, like, viable?"

"I have no idea," said Mark. "But can I have some lasagna, please?" 

"You can have all the lasagna, you sperm production powerhouse, you," said Jack. 

"... don't ever say that again," said Mark, making a face.

Jack burst out laughing, but he put a proper brick of lasagna on Mark's green plate.

* * * 

And then they were on the bed.

Other stuff had happened - they'd washed those dishes, they'd made out on the couch, they'd pressed together, breathing each other's breath, Jack getting lost in Mark's stale chocolate scent, which filled his head up like so much water. 

But now they were on the bed, and Mark was grinding against Jack. 

"I want... I really want to fuck you," he told Jack, as he kissed along Jack's chest, nipping at his shoulder, then shoving Jack's shirt up and beginning to kiss between his nipples.

"You're free to," said Jack, and he was panting, his tongue lolling out. 

"Can you... can you change shape?" 

"Right now?"

"Yeah," said Mark. "I want... I want to feel your fur against my cock." 

"Oh," said Jack, and he moaned at that, because... fuck, that was a really hot idea. 

The way he said it was hot - so much arousal in his voice.

Jack closed his eyes, concentrated.... and there was a sound.

It was an unusual sound, as if the air had been around one substance, and now it was around another, without any wind or whatnot taking place.

Jack was bigger, and his shirt was squeezing him - he had to get up on his elbows to actually remove it, which he did, with a sigh. 

"That's better," Jack said, and he kept sprawling, beginning to wag his tail.

"Oh yes," said Mark, as he began to kiss along Jack's body, nuzzling under his arms, then lower, biting his hips, nibbling his thighs.

"Mmm," Jack murmured, as Mark's head dipped forward, and Mark's mouth was around the head of his cock, as it slowly began to poke out of its sheath.

"Isn't it weird?" Mark pulled back. 

"Isn't what weird?" 

Jack blinked at him, addled with arousal. 

"It's getting hard already," said Mark, and he moved to sit in front of Jack, indicating the tent in his pants. "I'm not thinking about it - it's just getting hard, slowly, and it's... it's filling with blood.. sort of."

"Sort of blood?" Jack's hand curved around Mark's cock, and he squeezed it, gently.

"Well," said Mark, his voice breathless, "It's not technically b-b-blood, but it's... it's circulating, and... oh, fuck, please do that again, please!"

Jack chortled, shoving Mark's shorts down around his thighs, and he leaned in, gently licking the top of Mark's new cock.

It was almost anatomically perfect.

It was circumcised, which was not what Jack had expected, but then again, what did he know? 

He wrapped his lips around the head of it, leaning forward awkwardly, and Mark moaned, his hips hitching forward.

His cock was soft, velvety, and it was leaking a bit of pre into Jack's mouth.

It tasted like salt and like cold. 

* * * 

Time went away a bit - Jack just blew Mark, bobbing his head, careful of his gag reflex. 

It wasn't really a "just" though, was it? 

He lapped at the head of Mark's cock. He licked along the shaft. He took the thing as deep into his mouth as he could, which wasn't very far, but Mark seemed to enjoy it. He even nosed along Mark's balls, taking them into his mouth and sucking on them, just so that Mark's muscles would tremble under his fingers. 

"You're not so cold," Jack said, against the soft skin of Mark's dick.

It was like... well, it was like any other penis, in some respects, except it was cooler than your standard penis, but so much warmer than Mark's usual skin.

He sighed, and then he looked down at Jack with those big brown eyes of his. 

"Can I stick my dick in you?" 

"... you were just putting your dick in me," Jack said, his tone teasing.

"Oh my god," said Mark, "you're such a tease."

"A tease?" Jack waggled his eyebrows. "I've been putting out pretty well." 

Mark snorted, burying his fingers in Jack's hair. 

"I want to fuck you in the ass," said Mark. "I want to watch your face while I put it in, and I want to feel you clench tight and hot around me, until I cum across your stomach. How does that sound?"

"... sounds good," Jack squeaked. "I'm pro this plan." 

"Want me to get the lube?"

"We haven't used lube in an age," Jack said, lolling on his back and kicking his pants off, leaving him bare below the waist. 

Mark leaned down, mouthing along Jack's cock, and he was smiling, as Jack shuddered.

Jack's cock was red, and the knot was already beginning to spring out - he'd been sucking Mark long enough that his arousal had crested, almost peaked, and he was desperate, his tongue lolling out, panting like the dog he shared some of his self with. 

Mark's fingers were cold, and the lube was colder, as it slid into Jack's ass. His toes curled, and he made a startled whimpering noise, his fists clenching at the sheets, yanking at them, as Mark's fingers cautiously made their way inside of his ass.

"You're so warm," Mark murmured, "so warm, I can't get over how... warm you are, and you're so silky inside...."

"Can't you usually f-feel that?" Jack was humping against Mark's hand, his eyes squeezed shut, his tongue lolling out as he panted and panted. "How warm, I mean."

"I added some new nerves," said Mark, and he was feeling along Jack's ass. "I was curious... since you seem so responsive."

Jack shivered, as Mark pressed down on his prostate, and he tried to process what was being said. 

"Mark," said Jack, "how does it feel?" 

"It's... how do you walk around like this?" Mark's voice was thick, as he began to thrust his fingers into Jack, shallow, almost awkward. "How do you feel everything on your skin like that?"

"It's... you get used to it," said Jack, as another finger was added, and the burning stretch made his whole self shudder. 

"I never want to get used to it," Mark said, and he pulled his fingers out of Jack. "I think... I think you're ready. Please. I need to... I know I can do it again, but I want to do it _now_ , please!"

Jack grinned.

"I guess," Jack said. "You could do it. You could try." 

He was chuckling. 

"Really?" 

Mark's cock was flushed a dark, almost black and pink, and it was throbbing with Mark's almost blood. 

"Put it in me," said Jack, and he opened his legs wider, lifting them as well, resting his heels on Mark's shoulders. 

"You ready?" 

The head was cool (not cold), and it was velvety and damp against Jack's hole.

And then it was inside of him, and Jack was groaning, because it was pushing into him, it was making his toes curl against Mark's hair, as his head was thrown back, and his whole body was shaking.

"You're so... it's nice," Jack said, and then he laughed, which made Mark gasp. 

"You're so hot," Mark whimpered, "you're so... it's so...." 

He pushed himself all the way in, and then he was pulling out quickly, his cock spurting over Jack's belly, over Jack's cock, shuddering, panting, actual sweat dripping down his face, to splash on Jack's furry thighs. 

"Fuck," Jack mumbled, and he grinned up at Mark, trying not to laugh.

"... sorry," said Mark. 

"It's fine," said Jack, and he was grinning, taking up a bit of cum and licking it off of his fingers.

Then he wrinkled his nose, because... well, cum was cum, and even if it had hints of stale chocolate to it, it was still salty, bitter, and slimy. 

"How was that?" 

"That was pretty real," said Jack. "I came really fast the first time I was inside of something." 

Mark sighed. 

"At least I didn't cum in your face," Mark said, sounding slightly forlorn. 

"Don't worry about it," Jack said. 

"Can you... can I taste it?"

Jack held out his finger worth of cum, and Mark licked it up, his expression thoughtful.

"It doesn't taste like yours," said Mark.

"Well, no," said Jack. "It's yours, not mine."

"Oh," said Mark. "Can you... could you use it? To jerk of?"

"You mean like lube?" 

"Yeah." Mark was blushing harder. "I've done it for... you know, myself, with your cum, but I wanna see." 

Jack grasped his cock, slick with Mark's gooey cum, and he began to jerk himself off, paying special attention to his knot, squeezing it tightly, his other hand spreading the goo along his shaft.

"Fuck, fuck, oh... fuck," Jack groaned, and okay, maybe he was laying it on a bit thick, but fuck it, Mark deserved it, a little bit. 

He was humping into his hand, moaning, staring up into Mark's eyes, and his tongue was lolling out, as he planted his feet. 

"My prostate, press on it, please," he mumbled. "Please!"

"I gave myself one of those," Mark said. "I should let you try it next time."

"I will, I will, I promise, just... oh... _fuck_...."

Jack came across his own chest, his cum mingling with Mark's, and Mark's cum left him a little tingly, a little numb, but... holy fuck, Mark's fingers were filling him up, and Mark's eyes were limpid and sweet as he leaned down and kissed him, getting cum all over his own chest.

"That was... wow," said Mark. "No wonder you get so worn out."

"You gonna go back to normal?" Jack let Mark sprawl on top of him, enjoying the press of body on body, and the fact that Mark was so much cooler than he was. 

"In a sec," said Mark. 

Jack kissed him, and he sighed, as the cock pressed against his thigh began to change, back into the smooth tentacles. 

"That was neat," said Mark. "I'll try the next configuration next, I think."

"Next configuration?"

"You know. A vagina."

"... why am I surprised you can do that?"

"I honestly have no idea." 

“Maybe we’re both full of surprises,” Jack said, and he snuggled closer to Mark, licking at his jaw.

He was wagging his tail. 

Mark was smiling, against Jack’s mouth.

* * * 

“Vaginas are complicated,” said Mark, 

“Most body parts are,” said Jack, not looking up from his laptop. 

“Aren’t you gonna ask me why I said that? You didn’t even do a spit take.” 

“I’d have to be drinking something in the first place to do a spit take,” said Jack. 

“You’ve had spit takes without drinking something,” said Mark, flopping onto the couch next to Jack. 

“Well, yes,” said Jack, “but you’re popping out comments about body parts left, right, and center lately, so these days I kind of just… take it at face value, as it were.”

“I need to find new ways to surprise you,” said Mark. 

“Isn’t that what keeps relationships alive, anyway? Surprises?”

“I’ve got a pussy,” said Mark. “Please do something interesting with it, because this feels really strange.”

“What kind of strange?” 

“... empty,” said Mark. “I’m not used to feeling empty.” 

“I mean,” said Jack, closing his laptop and looking pensive, “I’d say you’re not empty-empty….”

“I’m not empty-empty, but I do want you to fuck me,” said Mark. “Please.”

“Well,” said Jack, and he was smiling with a few too many teeth as he looked up at Mark, his ears perked up and his tail wagging, “How could I refuse such a polite request?” 

* * * 

He lay Mark flat out on the rug, and he pulled Mark’s pants down. 

It was… well, it wasn’t what he was used to, seeing the curve of labia, not the bulge of a dick, or the flatness of his genital slit. 

Jack shoved his snout between Mark’s legs, and he nuzzled in, snuffling, his tail wagging, his hands kneading at Mark’s hips.

Mark made a surprised noise,

“It’s more… ticklish,” he said, his tone tentative.

“In a good way or a bad way?”

Jack used his long tongue to lap along Mark’s thighs, which were as familiar as ever. 

He licked up towards Mark’s sex, wagging his tail, inhaling Mark’s scent.

It was deeper this way, muskier, without that same sharp tang, but he undercurrent of stale chocolate. 

“Do you want me to eat you out?”

“Yes, please,” said Mark. 

Jack pressed closer, and he nosed at the cleft in Mark’s legs, between his labia. He rasped his tongue along Mark’s vulva, and Mark shuddered, his thighs beginning to go rigid on either side of Jack’s head. 

Jack made a pleased noise, and he used to fingers to hold Mark open, lapping at Jack’s labia with his long, long tongue. 

Mark shuddered, and he made a surprised noise, his heels digging into the rug.

“That’s… it’s… _fuck_!”

Jack grinned, his tail beginning to wag, and he slid his tongue inside of Mark, scooping more of that musky, darkness tinged slick from inside of him.

He used the tip of his tongue like a tattoo needle, jabbing at Mark’s clit, but Mark was sobbing and thrashing under him, still holding on to Jack’s hair, letting go to grab at his own.

Mark came, his hips arching off the floor, and Jack kept tapping at his clit until Mark was beginning to tense up again, and Jack pulled away, panting, a few stray hairs stuck to his whiskers. 

“Can I cum again?”

“You can _totally_ cum again,” said Jack. “You want to?”

“Oh fuck yes,” said Mark. 

“Well,” said Jack, “far be it from me to deny you a new experience.”

* * * 

He gave Mark four more orgasms, lapping, sucking, slurping. He humped the floor, nearly to an orgasm, before Mark shoved him away, sobbing. 

“Jack,” Mark said, “Jack, I need… I need something….”

“Do you want me to keep licking you?”

“Y-y-yes,” Mark panted. “But I also… I want you to… can you put your fingers in me?”

“Yeah,” said Jack. “Totally. Totally an option.”

His tongue was lolling out like it was a hot day, and his tail was wagging enough to kick up a breeze. 

Mark was tight, wet, clenching around Jack’s fingers as he slid them in, curving them carefully, and he pressed down when he found the change in texture, as Mark _shrieked_ and squalled under him.

“Oh my fuck, oh my… oh my fuck, oh fuck… oh….”

A spray of thin liquid got Jack in the face, and he was grinning, his lips wrapped around Mark’s clit, his tongue slobbering along whatever he could reach.

He helped Mark ride the orgasm, prolonging it as long as possible, but then Mark was pushing him away, and Mark was sobbing, shaking, slapping at the floor, twisting Jack’s hair in his fingers. 

“Please, please, please….”

He licked Mark gently, withdrawing his fingers from that tight, clenching coolness, still twitching from the aftershocks. 

“I need you in me,” Mark gasped. “I need… I need your cock, or your fingers, or… anything, I need you, please!”

Mark was sobbing, clenching around nothing, practically _begging_ , and his hands tangled into Jack’s hair, as Jack sat up, beckoning at his lap, where his cock stood out, his knot fully emerged from his sheath.

“This is gonna feel weird,” Jack warned, as Mark inched his way forward, hovering over Jack’s cock.

Jack rubbed the head of his cock against Mark’s entrance, between his labia, and Mark whimpered and sighed, his toes curling. 

“It’s… it’s intense,” he told Jack. “I like it, i think, But I think it might be a bit of a… a sometimes food. You know?”

“Yeah, I understand,” said Jack, using one hand to keep Mark’s balance, his other to keep his cock in place, more or less. 

“But I’m going to eat it, well and truly,” said Mark, and he took down all of Jack’s cock, all in one go, knot and all.

Jack choked, and Mark made a noise, half pained, half pleasure.

Mark squeezed around Jack, and Jack sobbed, his hips juddering forward, thrusting shallowly into Mark. 

It was cool - not cold, but cool - and it was velvety, slick. 

It was almost like being inside of Mark’s mouth, but it held him much, much tighter.

“Fuck, it’s so… full,” Mark said thickly, and he pressed his forehead against Jack’s, panting heavily. “I’m going to… it’s so much. It’s almost _too_ much.” 

“Do you want me to pull out?”

Jack’s snout was pressed into Mark’s neck, he lapped at it, then took it into his teeth, 

Mark groaned, and Jack’s thumb went to Mark’s clit, pressing down on it, rotating, and it was already so hard, so tender, that Mark was almost sobbing as he held on to Jack, almost sobbing. 

“Jack, Jack, it’s… Jack, oh fuck, it’s so different, please don’t stop, please don’t….”

Jack came inside of Mark. 

His knot was well and truly stuck, and he was pumping load after load inside of Mark, his whole back arching, his head limp against the couch. 

“It’s so hot, oh god,” Mark groaned, and Jack’s thumb kept rubbing across his clit, until Mark was squeezing around Jack’s knot again, and that seemed to bring in that much more cum - not even much, a bare trickle, but enough that it left Jack completely limp, his hand sticky with Mark’s cum, with his own. 

“Sorry,” Jack mumbled into Mark’s temple. “I’m… thingy. Organic. Not made of the same stuff you are.”

“It’s okay,” said Mark, and he shifted, a trickle of cum dripping out of him around Jack’s knot.

There’d be a deluge, when the knot finally shrank. 

“This has been… an amazing experience,” mumbled Mark. “How do you mortals get anything done?”

“A lot of practice,” said Jack, and he yawned so hard that his ears popped. 

He snuggled closer to Mark, his eyes drifting shut.

He was about to engage in another mortal wonder - sleeping.

At least Mark had plenty of experience with that! 

Judging by the way that Mark had started to snore, he was already experiencing it himself.

**Author's Note:**

> Like this fic? 
> 
> Check out my tumblr, theseusinthemaze.tumblr.com.
> 
> Like this universe?
> 
> Check out Rem's Tumblr, squishybons.tumblr.com!


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